Air conditioning system



Filed Aug. 30, 1937 3 Sheets-Sheet l N INVENTOR Clarence WNe-ssel]ATTORNEY Nov. 26, 1940. c. w. NESSELL AIR CONDITIONING SYSTEM Filed Aug.30, 1957 3 Sheets-Sheet 2 's'sll INTENTOR ClarenceW Ne ATTORNEY Nov. 26,1940.

C. W. NESSELL AIR CONDITIONING SYSTEM Filed Aug. 30, 1937 3 Sheets-Sheet3 an v EN a E 3 E Clarence WNessell INVENTOR ATTORNEY Patented Nov. 26,1940 UNITED STATES PATENT OFFICE AIR CONDITIONING SYSTEM ApplicationAugust 30, 1937, Serial No. 161,591

, 11 Claims.

. This invention is directed to a fluid circulating system and moreparticularly to a heating system. In a building having a plurality ofspaces or zones to be heated, it is common to provide a warm air furnaceconnected by ducts to the various spaces to be heated, and a blower forcirculating air through the furnace and through said spaces. Inorder tocontrol the temperature in each space individually, each space may beprovided with a thermostat, and a damper motor under the control of eachthermostat, for operating dampers in the various warm air ducts, topermit or prevent the flow of air into each space, depending uponwhether the thermostat in the particular space is calling for heat 01 issatisfied. In such a system, it is unnecessary to circulate air at asfast a rate when only one space is calling for heat as when more thanone space is calling for heat. I therefore provide automatic means tooperate the blower to circulate air at one rate when only one space isdemanding heat, and to operate the blower to circulate air at a higherrate when more than one space is demanding heat, and also to stop theblower when none of the spaces are demanding heat, since, when none ofthe spaces are demanding heat, all the warm air ducts are closed bytheir respective dampers, and there is no necessity or advantage inoperating the blower at this time. It may happen that one space in thebuilding is larger than the others, or for some other reason, such asits exposure, may require a larger amount of heat to raise itstemperature, and accordingly, I have provided means to operate theblower to circulate air at a higher rate when this particular space iscalling for heat than when any other one space is calling for heat.

I have illustrated two common means for varying the amount of aircirculated by the blower, but it should be understood that my inventionis not limited to the two ways illustrated. In one form of theinvention, a two-speed fan is illustrated, and in another form,adjustable dampers controlling the input to the fan are provided.

While my invention is illustrated in connection with a warm air heatingsystem, it is equally applicable to any other type of heating systemsuch as a hot water heating system, and to any other fluid circulatingsystem, such as a cooling, 5 ventilating, r humidity controlling system,and it should therefore be understood that it is not limited to a warmair heatingsystem.

One of the objects or my invention is, therefore, to provide an improvedfluid circulating 5! system.

Another object of my invention is to provide a fluid circulating systemwherein fluid is circulated at varying rates of flow in accordance withthe number of spaces being supplied with 5 fluid.

Another object of my invention is to provide a fluid circulating systemwherein fluid is circulated at different rates of flow in accordancewith the size and/or number f spaces being supplied with fluid.

More specifically, it is an object of my invention to provide a warm airheating systemwherein a pluralit of spaces are to be heated, and whereinone space requires more heat than the others, with thermostatic meansfor controlling the flow of air to the various spaces, together withmeans for circulating air at a high rate when any two spaces, or theaforementioned one space is calling for heat, for circulating air at alow rate when any other single space is calling for heat, and to stopthe air circulation when none of the spaces are calling for heat.

Other objects will become apparent upon a study 01' the specification,claims and appended drawings, in which like reference charactersrepresent like parts in the different views, and in which:

Figure 1 is a schematic view of one form of my invention,

' Figure 2 is a view of a second form of my invention, and

Figure 3 is a view of still another form of my invention.

Referrin now to Figure 1 a heating plantis illustrated, said plantcomprising a warm air furnace I0 having a fuel supply line H, a warm airduct 12 havin branch ducts i3, I4, 15, and I8, communicating withregisters l1, l8, I9, and 20 located in the spaces to be heated. A fan2| is provided for circulating air through the furnace and spaces to beheated, there being a return air duct 22 communicating with the inlet ofthe fan. The furnace is also provided with the usual flue gas stack 21.I 5

For driving fan 2!, I have provided a motor 23 connected to the fan bymeans of a belt 24, said belt travelling over pulleys 25 and 26 on themotor and fan, respectively. The motor 23 is or the condenser inductiontype and comprises an armature 30, a field winding 3|, a second fieldwinding 32, and a condenser 33. windings 3i and 32 are connectedtogether at one end thereof and condenser 33 is connected to the otherend of winding 32. An autotransformer 35 is provided for varying thecurrent through winding 23, thereby varying the speed of the motor.

In the fuel supply line I I is a valve 38, said valve having anupstanding stem 39 to which is connected an armature 40, this armaturebeing surrounded by a. solenoid 4i. Energization of solenoid 4I causesarmature 40 to move upwardly and through the stem 39 causes the valve tomove to open position. Any suitable means such as a spring (not shown)may be provided for moving the valve to closed position when solenoid4i'is deenergized.

Mounted in the warm air chamber of the furnace is a bimetallic element42 connected at one end to a rod 43, the other end of said element 42being held against movement by being rigidly connected to the wall ofthe furnace or otherwise suitably securedagainst movement. The rod isconnected to the mercury switches 44 and 45 in a known manner, so thatrotation of rod 43 by the bimetallic element dflcauses switches 44- and45 to be tilted. Switch 44 is provided with contacts 46 and 4t", andswitch 513 provided with contacts 48 and 49. Switch 45 is designed to beclosed at a lower temperature than is necessary to close switch 44.

For controlling the operation of the motor 23 and the energization ofsolenoid M, a relay generally indicated by the reference character 60 isprovided. This relay comprises a coil GI, an armature 62, switch arms 63and 64, and stationary contacts 65 and 68 cooperating with the switcharms 63 and 64, respectively. When coil IN is energized,'switch arms 63and 64 are moved out of engagement with their respective contacts 65 and66, and when deenergized the switch arms move into engagement with theirrespective contacts.

For controlling the speed at which motor 23 operates there is provided asecond relay generally indicated by the reference character 50. Thisrelay comprises a coil 5|, armature 52, a switch arm 53, and contacts 54and 55. When coil 5| is deenergized, switch arm 53 is in engagement withcontact 55,'and when said coil is energized the arm 53 is moved intoengagement with contact 54.

For supplying power to the relays I have provided a transformer 10, saidtransformer having a high tension coil II and a low tension coil 12, thehigh tension side of the transformer being connected to lines I3 and I4which are in turn connected to a suitable source of power (not shown).

The spaces to be heated are .designated by the maturei 41 drives'throughsuitable reduction being limited by the bottom of the slot I62 in whicharm i8I travels. This damper motor operates until the damper is in wideopen position, at which point it stalls, and maintains the damper inthis position until the energizing circuit to the motor is broken. Aspring I63 is provided for 'returning the damper and the motor to itsoriginal position after it has been deenergized.

Cams 30, 3I, IIO, IIl, I30, and Hi similar to cams E50 and I5! in spaceM0, are located in spaces 30, E00, and E20 as shown. Cooperating withthe various cams are switch arms 92, 93, M2, M3, I32, 833, I52, and I53,theseswitch arms being held in engagement with contacts Q4, 95, Il i,Hi5, stop I34, contact I35, stop 55%, and contact l55, respectively,when the damper motors in each space are deenergized, When the cams arerotated through 180 the respective switch arms are moved into engagementrespectively with contacts 55, 3?, H8, IIlI, I38, I32, E55, and

I5'l, and in this position, the dampers in the respective spaces arewide open.

OPERATION or SPECIES or FIGURE 1 With the parts in the positionsillustrated none of the thermostats in the various spaces are callingfor heat, the blade of each thermostat being out of engagement with itsrespective contact. Relay coil 6! is energized, thereby holding switcharms 63 and 64 out of engagement with contacts 65 and 66, the energizingcircuit for this relay being as follows: from one side of low tensioncoil I2 of transformer I0 through conductors 200, 20 I, switch arm 93,contact 95, conductor 202, switch arm II3, contact II5, conductor 203,switch arm I33, contact I35, conductor 204, switch arm I53, contact I55,conductor 205, through the coil 65 and conductor 208 to the other sideof transformer coil I2. Since switch arms 63 and 64 are out ofengagement with their respective contacts it will be apparent that thereis no circuit through solenoid M or motor 23.

Should the thermostat in any one of the spaces call for heat a circuitthrough the respective damper motor is established. Assume thethermostat in space is calling for heat, the damper motor in this spacewill be energized by the following circuit: from line I4 throughconductors I10, I'II, I12, I13, I88, bimetallic element 82, am. 83,contact 84, conductor I80 through the field coil of the motor, andconductors I8I, I82, I83, and I84 back to the line I3. It will beobvious that the damper motor in any of the other spaces will 'beenergized through a similar circuit upon a call for heat by thethermostats in those spaces,

Energization of the damper motor in space 80 causes rotation of cams andSI through at which time the. damper in said space is in open positionand further movement is prevented, as described in connection with thedamper motor I48 and'damper I45. Switch arms 92 and 93 are now inengagement with contacts 98 and 91 as will be apparent. The circuitthrough relay coil BI is now broken by reason of the opening of co tact95, whereupon switch arms 63 and 64 move into engagement with theirrespective contacts 65 and 66. It will be obvious that the energizationof any of the damper motors with the attendant shifting of therespective switch blades will likewise cause relay coil BI to becomedeenergized.

Engagement of switch blade 53 with contact 55 causes a circuit throughsolenoid M as follows: from line '54 through conductor Ziil, switch arm63, contact 55, conductor 25 I, solenoid it, and conductor bacls to theline 13. Energization of solenoid 4| causes opening of valve 33 aspreviously described whereupon fuel is supplied to the furnace I3through pipe II, the furnace thereby becoming hot.

When the temperature rises a suflicient the mercury therein and energyis supplied to motor 23. Autotransformer 35 is connected to the sourceof power from the line 14, through conductor 2|5, contacts 45 and 43 ofswitch 45, conductor 2I5, contact 55, switch arm 54, conductor 2I1, tap2|5 on the transformer through the transformer coil to tap 2 I3, andthrough conductors 223, 22I to line 13. Relay 5| is at presentdeenergized, and switch 53 is in engagement with contact 55, and thevoltage impressed on coil 3| is less than that impressed on thetransformer, current flowing through the coil 3| through the followingcircuit: from the coil 3| through conductors 225, 223, terminal 2|3 ofthe transformer, through part of the transformer 35 to the tap 224,through conductor 225, contact 55, switch arm 53, and conductor 221 tothe other side of field winding 3|. Field winding 32 and condenser 33 isconnected to the transformer through the following circuit: fromterminal 2|9 of .the transformer, through conductors 223 and 225, coil32, condenser 33, to terminal 222 of the transformer.

winding 3| is considerably less-than the line voltage.

When relay coil 5| is energized and switch blade 53 is moved intoengagement with contact 54 the voltage across coil 3| is increasedwhereupon the motor travels at high speed. The voltage on coil 3| is nowgreater than line voltage, the coil now being connected to transformer35 as follows: from the fleld winding 3| through conductors 225, 223,terminal 2|5 of the transformer, through part of the transformer to tap223, conductor 225, contact 54, switch arm 53, and conductor 221 to theother side of field winding 3|. It is therefore apparent that thevoltage on coil 3| is increased upon energization of relay coil 5| andthat the motor will operate at high speed.

Assume now that any other space also requires heat, as for example,space I23, the energization of the damper motor for this space causescams I33 and III to move through 180 whereupon switch arms I32 and I33are in engagement with contacts I35 and I31. After the temperature ofthe furnace rises to a high predetermined value at which contacts 45 and41 are closed by the tilting of switch 44a circuit through relay coil 5|is established, this circuit being as follows: from the low tension coil12 of transformer 13 through conductors 233, 23I, switch arm 33, contact51, conductors I53, I5I, I34, contact I31, switch arm I33, conductor233, contact H5, switch arm 3, conductors 252, 244, contact 55, switcharm 52, conductors 233, 232, contacts 45, 41, conductor 233, relay coil5|, and conductor 234 back to the low tension coil 12. Energizationofrelay coil 5| causes switch arm 53 to move into engagement with contact54, whereby the high speed circuit through the motor, previouslydescribed, is established, and the motor drives the fan at high speed.

A call for heat by any combination of two zones will cause theenergization of coil 5| through a circuit similar to that describedabove.

The motor now. operates at low speed since the voltage on field- ZoneI43 is what is termed a Master zone." That is, it may require more airto be circulated therethrough when there is a. call for heat thereinthan any of the other zones, either by reason of its size or itsexposure, for example. For this reason a circuit established throughrelay coil 5| should this space alone require heat. When switch arm i 43of thermostat I4| moves into engagement with contact I44, cams I 53 and|5| are rotated through 183, as previously described, moving switch armsI52 and I-53 into engagement with contacts I55 and I51, therebyestablishing the following circuit through relay coil 5|, it beingassumed that the temperature of the furnace has risen to the value inwhich contacts 45 and 41 are closed, this circuit being as follows: fromthe low tension coil 12 through conductors 233, 24|, contact I55, switcharm I52, conductors 23I, 232, contacts 45, 41, conductor 233, throughrelay coil 5| and conductor 234 to the other side of low tension coil12.

It will therefore be seen that upon a call for heat in any one zone,that the supply of fuel to the furnace is started. It will also be seenthat upon a cail for heat by any single zone with the exception of zoneI43 that the motor 23 is operated at low speed, after the switch 45 hasclosed because of a sufficient rise in temperature of the furnace, andthat a call for heat by any two zones, the motor 23 is operated at highspeed, assuming that switch 44 has been moved to closed position. It hasalso been pointed out that upon a call for heat by zone I43 alone themotor is operated at high speed. When all of the thermostats have becomesatisfied the damper motors are returned to their original positions asillustrated under the influence of their respective springs such asspring I 53 of damper motor I45, whereupon relay coil 5| is againenergized through the circuit originally described, switch arms '53 and54 are moved to open positions, the supply of fuel to the furnace is cutoi! by reason ,of the deenergization of solenoid 4|, relay coil 5|isdeenergized and the supply of power to the motor 23 is cut oil by theopening of switch 54.

Description of Figure 2 In Figure 2 I have illustrated a system similarto that of Figure 1 except that a single speed fan motor is provided andthe change in rate 50 of circulation of air is controlled by suitabledampers provided in the return air duct 22 to the fan 2|.

The motor is represented by the reference character 253 and is providedwith contacts 3|3 and 3, said motor being connected to the fan by a belt24 passing over pulleys 25 and 25 of the motor and fan, respectively.

In the return air duct are shown dampers 255, connected to a. dampermotor "I by means of link 252 pivotally connected at its other end toarm 253 connected to a shaft 254 which is driven by the motor 25I. Stops255 and 255 are provided to limit the movement of arm 253, a spring 251moving arm 253 against stop 255, arm 253 being held against stop 255 inwhich position the dampers 255 are in their wide open position when themotor is energized.

Switches 44 and 45 operated by the bimetallic element 42 are identicalwith those described in Figure 1. A third switch 25I operated by thewith contacts 252 and 253 which are normally closed and which are openedwhen the temperatherefor are identical with those shown in Fig-' ure 1and for this reason have not been illustrated in this figure.

OPERATION or SPECIES OF FIGURE 2 With none of the zones requiring heat,relay coil 6| is energized through the following circuit: from lowtension coil 12 of transformer 10 through conductors 304, 303, switcharm 93, contact 95, conductor 302, switch arm II3, contact II5,conductor 30I', switch arm I33 and contact I35, conductor 300, switcharm I53, contact I55, and conductor 205 through relay coil 6| andconductor 206 back to the other side of transformer coil 12.

Switch arms 63 and 64 are accordingly held out of engagement with thecontacts 65 and 66 and no current flows to the solenoid M or motor 250.

Upon a'call for heat in any one of the zones the damper motor for thatparticular zone operates to open the damper in the register for thatzone whereupon the cams are rotated through 180 thereby breaking theenergizing circuit for relay coil 5|. Solenoid 41 is now energizedthrough the following circuit: from line 14 through conductor 2I0,switch arm 63, contact 65, conductor 2, solenoid 4I, conductor 2I2,contacts 252, 253 and conductor 2I2 back to line 13. Fuel is nowsupplied to the furnace I0 whereupon the temperature is increased untilswitch 45 is tilted to close contacts 48 and 49 and current throughmotor 250 flows as follows: from the line 14 through conductor 3I0,contacts 48, 49, conductor 3| I, contact 66, switch arm 54, conductor3I2, terminal 3I3 through the motor winding, terminal 3I4 and conductor3I5 back to the line 13. It is therefore apparent that upon a call forheat by any one zone fuel is supplied to the furnace and after apredetermined rise in temperature in the heating chamber thereof motor250 operates to circulate air through the furnace and through the spacein which the damper has been opened, or the space requiring heat. Theamount of air circulated is at a low value as long as damper motor 26Iis deenergized, holding dampers 260 in the positions as illustrated.

Should there be a call for heat in any two or more zones the dampermotor 26I will be energized, or if zone alone, this zone being themaster zone in this modification, is requiring heat, the damper motorZBI willbe operated. Assume for the present "that zenes.l00 and I20require heat. It will be understood that cams IIO, I I I, I30, and I3Ihave been rotated through 180 by their respective damper motors. Ifswitch 44 has been tilted to close contacts 45 and 41 because of asuflicient rise in temperature in the heating chamber of the furnace,damper motor 26I will be energized through the following circuit: fromlow tension coil 12 through conductors 304, 303, switch arm 93, contact95, conductor 302, switch arm II3, contact II1, conductors 33I, 335,332, contact I31, switch arm I33, conductors 30I, 340, contact I I6,switch arm 2, conductor 331, contact 94,v switch arm 92, conductor 32I,contacts 46, 41 of switch 44, conductor 322 through the damper motor 26Ito con-, ductor 323 and back to the other side of low tension coil 12. Asimilar circuit may be traced through the damper motor when anycombination of two zones is calling for heat.

Assume now that zone 80 alone is calling for heat, this zone being themaster zone," the damper motor 26I is. operated to move the dampers 260to the open position, the circuit through the motor now being as followsit being understood of course that cams and 9I have been rotated throughfrom the low tension coil 12 through conductors 304, 320, contact 95,switch arm 92, conductor 32I, contacts 46 and 41 of switch 44, conductor322 through the damper motor, conductor 323 to the other side of lowtension coil 312. It is assumed, of course, that the temperature of theheating chamber is suiiiciently high to cause switch 44 to be tilted toclosed position,

Switch 25I is designed to open the circuit throughsolenoid 4| whereuponthe flow of fuel to the furnace is cut off, upon the attainment of ahigh predetermined temperature in the furnace and is designed to preventthe furnace from becoming too hot.

It will thus be seen that the system illustrated in Figure 2 is similarto that shown in Figure 1 except that the two-speed motor illustrated inFigure 1 is substituted by a single speed fan motor and a damper motorby means of which the amount of air supplied to the fan may be varied.

Description of Figure 3 The structure shown by this figure is identicalwith that shown in Figure 1 except that in this figure the parts are soconnected that no one zone alone will cause high'speed operation ofmotor 23. In other words, the master zone has been eliminated andsubstituted by a zone which is similar to the others. It is believedthat further description of the apparatus shown is unnecessary in viewof its similarity to Figure 1.

OPERATION OF SPECIES OF FIGURE 3 Solenoid 4| controlling the operationof valve 38 is energized as in Figure 1 when relay coil BI isdeenergized. The energizing circuit for this coil when none of the zonesare calling for heat is as follows: from low tension coil 12 throughconductor 400, switch arm 93, contact 96, conductor 40I, switch arm H3,contact II5, conductor 402 switch arm I33, contact I35, conductor 403,switch arm I53, contact I55, conductor 4 through coil GI and backthrough conductor 420,

to the other side of low tension coil 12. This circuit is broken uponthe moving of any one of the above named switch arms away from itsrespective contacts, which takes place when there is a i call for heatin any one of the zones, whereupon coil 6| is deenergized and a circuitthrough solenoid 4| identical to that described in Figure 1 isestablished. The motor 23 is now operated at low speed, assuming thatswitch 45 has been tilted to the position in which contacts 48 and 49are closed by reason of the attainment of a predetermined temperature inthe heating chamber of the furnace, and will continue to thus run aslong as switch 64 is in engagement with contact 66 and switch 53 is inengagement with contact 55. The motor runs at high speed only when relaycoil 5| is energized thereby moving switch arm 53 into engagement withcontact 54 as in Figure 1. This will not take place until at least twoof the zones are calling for heat, there being no single zone that whencalling for heat will establish a circuit through this coil. If any twozones, as for example, zones 80 and I40 are calling for heat c'ams 90,9|, I50, and I5I are moved through 180 and a circuit is establishedthrough coil 5| as follows, it being assumed that switch 44 aazaaee hasbeen tilted to close contacts 48 and 4'! by the bimetallic element 42:from the low tension coil 12 through conductor 400, switch arm 93,contact 91, conductors M2, H6, H1, H8, 5, contact I51, 1

switch arm I53, conductor 403, contact I35, switch arm I33, conductor402, contact H5, switch arm H3, conductors 4M, Mil, contact 95, switcharm 92 through conductor 435, contacts 48 and 41 of switch 44, conductor233, relay coil 5|, and conductor 234 back to the other side oi, coil12. ment of switch arm 53 into engagement with contact 54 and causeoperation of the motor at high speed as described in connection withFiggure 1.

One more illustrative circuit will be traced through the relay coil 5!.Assuming now that zones 80 and I20 are calling for heat, the circuitthrough the coil 59 is now as follows: from transformer 12, conductor400, switch arm 93, contact 91, conductors H2, H5, 4H, 4", contact I31,switch arm 133, conductor 402, contact H5, switch arm-| l3, conductors40!, 401, contact 95, switch arm 92, conductor 435, contacts 43, 41,conductor 233, relay coil 5| and conductor 234 back to the other side oftransformer coil 12.

It is therefore seen that I have devised a warm air heating systemwherein damper motors to the various zones to be heated are undercontrol of separate thermostats in each zone and wherein air iscirculated at a low rate in response to a call for heat in any singlezone, and is circulated at a high rate upon a call for heat for morethan one zone. Also a master zone may be provided which causes operationof the air circulating means at a high rate upon a call for heat by thatzone. It will be obvious that my invention is capable of manymodifications and I wish it to be understood that the invention is to belimited only by the scope of the appended claims.

I claim as my invention:

1. In a heating system, a heating chamber, means for heating saidchamber, means for causing a forced circulation of fluid through saidchamber and through a plurality of spaces to be heated at aplurality ofpredetermined rates of flow, temperature responsive means in each space,means controlled by the temperature responsive means for controlling theflow of fluid into each space, a plurality of electrical circuits forcontrolling the rate of flow or fluid by the circulating means, meansresponsive to the operation of the flow control means when said means isoperated to admit fluid to any one space only to energize one electricalcircuit to cause operation 01' the fluid circulating means-ataupredetermlned low rate of flow, means responsive to the operation ofthe flow control means when said means is operated to admit fluid tomore than one space to energize a second electrical circuit to causeoperation of the fluid circulating means at a predetermined high rate offlow, and means whereby all the energizing circuits to the fluidcirculating means are deenergized when none of the temperatureresponsive means are calling for heat.

2. In a heating system, a heating chamber, means to supply heat to saidchamber, means to caused a forced circulation or fluid through saidchamber and into a plurality of spaces to be heated at any one of aplurality of predetermined rates, means to control the flow of fluid tothe various spaces, there being one space having greater heatrequirements than the other spaces, means responsive to the operation ofthe flow control means to admit fluidto the last mentioned space Theenergization of coil 5! will cause move to cause operation of the iiuidcirculating means at a high predetermined rate, means responsive to theoperation 01 the flow control means to admit fluid to any other singlespace to cause oper ation of the fluid circulating means at a lowpredetermined rate, and means responsive to the operation of the flowcontrol means to admit fluid to any two spaces to cause operation of thefluid circulating means at a high predetermined rate. I

3. In a heating system, a heating chamber, means to supply heat to saidchamber, means to cause a forcible circulation of fluid through saidchamber and into any one or more of a plurality of spaces selectively atdifferent predetermined rates dependent upon the spaces to be heated,means for controlling the flow oi" fluid into the various spaces, meansfor operating the fluid circulating means at a low predetermined rate inresponse to the operation of the flow control means to admit fluid toany one space only, means for operating the fluid circulating means at ahigh predetermined rate in response to the operation of the flow controlmeans to admit fluid to more than one space, and means for stoppingoperation of the circulating means and the heating means in response tothe operation of the flow control means to prevent flow of fluid to anyof the spaces.

4. In an air circulating system, a fan for circulating air into aplurality 01' spaces, a motor for operating said Ian, said motor havinghigh speed and low speed circuits, means for controlling the flow of airinto said spaces, one of said spaces requiring a greater flow of airthan any of said other spaces, means energizing a high speed circuit ofthe motor in response to operation of the controlling means to causeflow of air to the last mentioned zone, means energizing a low speedcircuit of the motor in response to operation of the controlling meansto cause flow of air to any other single zone, and means energizing ahigh speed circuit of the motor in response to operation 01' thecontrolling means to cause flow of air into any two spaces.

5. In an air circulating system, means for circulating air into aplurality oi spaces, a damper movable between two positions for varyingthe output oi. said air circulating means, in one position of which thedamper permits minimum air flow and in the other position of which itpermits maximum air flow, means for controlling the flow of air to thevarious spaces; means responsive to movement of the air flow controllingmeans to a position causing air flow into any one space only for causingoperation of the air circulating means and for positioning the damper inthe position of minimum air flow, means responsive to movement of theair flow controlling means to a position causing flow of air in morethan one space for causing operation of the air circulating means andfor positioning the damper in the position of maximum air flow, andmeans for stopping the air circulating means when the air flowcontrolling means is in a position preventing flow of air into any ofthe spaces.

6. In a heating system, a plurality of spaces to be heated, a heater,circulating means for circulating fluid through the heater and throughthe spaces to be heated at varying rates of flow, means controlling theflow of fluid into each of said spaces, a motor for operating each ofsaid controlling means, temperature responsive means in each space forcontrolling the operation of the.

motor in that space, switch means operated by each of said motors, meansnormally maintaining the circulating means inoperative when none of themotors are operated to admit circulation of heating fluid through saidspaces, circuit means for causing said circulating means to operate tocirculate fluid at a low rate of flow in re sponse to the actuation ofthe switch means by one of said motors when said motor is actuated toadmit circulation of fluid to the space controlled by said motor, andcircuit means for causing operation of said circulating means to operateto. circulate fluid at a high rate of flow in response to the actuationof the switch means by any two or more of said motors when said motorsare actuated to admit .circulation of fluid through the respectivespaces. a

'7. In a heating system, a plurality of spaces to be heated, a heater, atwo-speed fan for circulating air through the heater and the spaces tobe heated, dampers for controlling the flow of air into each of saidspaces, motors for operating said dampers, temperature responsive meansin each space for controlling the motor in that space, switch meansoperated by each damper motor, means normally maintaining the faninoperative when none of the damper motors are operated to open theirrespective dampers, circuit means for establishing a low speed circuitto the fan in response to the actuation of the switch means by one ofthe damper motors, and circuit means establishing a high speed circuitto the fan in response to the actuation of the switch means by any twoof the damper motors when these motors are operated to open.

their respective dampers.

8. In a heating system, a heater, a motor fan unit having high and lowspeed circuits for circulating air through said heater and through thespaces to be heated, a damper in each space for controlling the flow ofair into said spaces, a separate motor for operating each damper, cammeans connected to each motor, a pair of switches operated by each cammeans, each switch having a first position when its controlling motor isin a position wherein the damper operated thereby is closed to preventthe admission of air into the respective space, and each switch having asecond position when its controlling motor' is in a position wherein thedamper operated thereby is open to admit air into the respective space,means preventing operation of said motor fan unit when all of saidswitches are in the first positions, means connecting the low speedcircuit of said motor fan unit to a source of power in response to themovement of a single pair of switches to the second position, and

- means connecting the high speed circuit of said motor fan unit to asource of power in responsev to movement of more than one pair ofswitches to the second positions.

the spaces to be heated, a damper in each space for controlling the flowor air into said spaces. a separate motor for operating each damper,temperature responsive means in each space controlling the operation ofthe respective damper a switch operated by each cam, each switch havinga first position when its controlling motor is in a position wherein thedamper operated thereby is closed to prevent the admission of air intothe respective space, and each switch having a second position when itscontrolling motor is in a position wherein the damper operated therebyis open to admit air into the respective space, means preventingoperation of said motor fan unit when all of said switches are in thefirst positions, means connecting the low speed circuit of said motorfan unit to a source of power in response to the movement of a singlepair of switches to the second positions, and means connecting the highspeed circuit of said motor fan unit to a source of power in response tomovement of more than one pair of switches to the second positions.

10. In a conditioning system, means for causing a forced circulation offluid through a plurality of spaces to be conditioned at varying ratesof flow, means controlling the admission of fluid to each space, meansoperating said controlling means, space condition responsive meanscontrolling said operating means, switch means, operated by saidoperating means, controlling a circuit through said fluid circulatingmeansto cause operation of said means to circulate fluid at a low ratewhen the controlling means is operated to admit air to one space only,and controlling a second circuit through said fluid circulating means tocause operation of said means to circulate fluid at a high rate when thecontrolling means is operated to admit fluid to any two or more spaces.

11. In a conditioning system, means for causing a forced circulation offluid through a plurality of spaces to be conditioned at varying ratesof flow, said spaces including one space requiring more fluid than theothers, means controllin the admission of fluid to each space, means op--motor, a pair oi'cams operated by each motor,

erating said controlling means, space condition responsive meanscontrolling said operating means, switch means, operated by saidoperating means, controlling a circuit through said fluid circulatingmeans to cause operation of said means to circulate fluid at a low ratewhen the controlling means is operated to admit fluid to any singlespace except said one space, controlling a second circuit through saidfluid circulating means to cause operation of said means to circulatefluid at a high rate when the controlling means is operated to admitfluid to more than one space, and also when the controlling means isoperated to admit fluid to said one space only.

CLARENCE W. NESSELL.

